Temperature control device



Oct. 24, 1950 c; F. ALSING TEMPERATURE con'moz. DEVICE 2 Sheets-Sheet 1 Filed Oct. 25, 1945 INVENTOR CARL F. ALsmG. BY%OI 5:,

WITNESSES:

ATTORNEY Oct. 24, 1950 c. F. ALSING rmmm coN'moL nnvxcs 2 Sheets-Sheet 2 Filed Oct. 25, 1945 INVENTOR CARL E Aums. @M ATTORNEY Patented Oct. 24, 1950 TEMPERATURE CONTROL DEVICE Carl F. Alsing, Wilbraham, Mass assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 25, 1945, Serial No. 624,503

16 Claims. ('01. 62-116) This invention relates to refrigerating apparatus and more especially to secondary volatile novel means for regulating the flow of refrigerant in a secondary refrigerant circuit in such a manner that the temperature of a thermally-insulated chamber cooled by the circuit remains constant in varying ambient temperatures.

It is a further object of the invention to provide novel means for cooling two compartments of a refrigerator to different temperatures and maintain each of said temperatures constant in varying ambient temperatures but utilizing only one primary refrigerating system controlled by a single thermostat.

These and other objects are effected by th invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a vertical section of a refrigerator embodying the invention with parts shown somewhat schematically;

Fig. 2 is a section on the line IIII of Fig. 1;

Fig. 3 is an enlarged vertical section of the controlling mechanism of the secondary refrigerating system;

Fig. 4 is a section on the line IVIV of Fig. 3; and

Figs. 5, 6, and '7 each show an enlarged vertical section of a modified form of the controlling mechanism of this invention.

Referring now specifically to the drawings, the

30. The compressed refrigerant vapor is transformed into a liquid in the condenser 28 and is returned through a capillary tube 32 to the evaporator 22. A portion 34 of the capillary tube 32 is secured in heat exchange relationship with a portion 36 of the suction conduit 26. A fan 33 driven by an electric motor 40 draws air through the condenser 28 to cool the same. A thermostat 4| controls the compressor to maintain the temperature of the upper compartment i8 at the desired point.

The lower compartment is cooled by a secondary volatile refrigerant circuit 42 having an evaporative portion '44 in the compartment and a condensive portion 45 in heat transfer relationship with the primary evaporator 22 for transforming the refrigerant vaporized in the evaporative portion 44 into a liquid. The conreference numeral l0 designates a refrigerator having a thermally-insulated food storage chamber E2 in the upper portion thereof and a machine compartment below the storage chamber H2. The storage chamber I2 is divided by a partition l-B into an upper compartment is for the storage of frozen foods and into a lower compartment 20 for refrigerated storage at above -freezing temperatures.

pressed vapor to the condenser 28 through a tube 55 I densive portion 46 comprises a tube 38, the entrance 50 of which communicates with the upper portion of a vessel 52 and the exit 54 of which communicates with the upper end of a vertical tube 55 passing through the vessel 52. The upper portion 56 of the tube 55 is located in the vessel 52 and forms a vapor-lift pump which draws refrigerant liquid from the vessel 52 through an opening 60 in the tube 55 when the upper portion 55 is supplied with refrigerant vapor. The lower portion 51 of the tube 55 extends downwardly from the vessel 52 into the insulation of the food storage chamber l2 and is closed at its lower end. A portion 58 of the capillary tube 32 is wrapped in heat exchange relationship around the lower portion 51 of the tube 55 to heat the refrigerant liquid therein and supply the vapor for the vaporlift pump.

The vessel 52' contains a pipe 62 extending to. and secured to, the bottom of the vessel 52. The upper end of the pipe 62 is open and is located somewhat below the upper wall of the vessel 52. The evaporative portion 44 comprises a tube having an entrance 63 communicating with the lower portion of the pipe '62 and an exit communicating with the upper portion of the vessel 52. An upwardly arched tube 64 is secured in the vessel 52 with one of its ends 66 directed downwardly into the upper end of the pipe 82 and with its other end communicating with the interior of the vertical tube 55 at about the same level as the upper end of the pipe 62.

Operation The refrigerant vapor condensed in the condensive portion 48 flows into the vertical tube 55 and through the openingtli into thewessel 52.

, -a,'c27,ese

The vessel 52, together with the tube 55 and the walls of'the pipe 62, forms a trap for the-refrigerant liquid of such volume that the liquid refrigerant condensable by'the condensing por-.

tion 46 from the secondary volatile refrigerant circuit 42 fills the trap to the level of the upper 4 end of the pipe 62. When the trap is full, further condensation of the secondary refrigerant stops except for the amount necessary to cool the vessel 52 and the tube 55.

The tube portion 51", when warmed by the portion 58 of the capillary tube 32, generates refrigerant vapor which actuates the vapor-lift pump 56. This pump, thereupon, draws liquid refrigerant through the opening 60 and forces liquid refrigerant mixed with refrigerant vapor through the tube 64 into the pipe 62.

The pipe 62 is of sufiicient internal diameter to allow separation between the refrigerant vapor and the refrigerant liquid and the refrigerant liquid will run downwardly into the evaporative portion 44 and the refrigerant vapor will pass upwardly into the entrance end 5|] of the condensive portion 46 of the secondary refrigerant circuit 42. The refrigerant liquid in the evaporative portion 44 vaporizesand cools the lower compartment, 20, and the resulting refrigerant vapor passes through the exit 65 of the evaporative portion 44 into the vessel 52 and thence into the entrance 5!) of the condensive portion 46 where it is condensed and flows downward as a liquid through the exit 54 of the condensive portion 45. The downward flow from the exit 54 of the condensive portion 46 meets with the upward flow of the refrigerant liquid and vapor in the tube 56 and is forced directly through the tube 64 into the open end of the pipe 62 to continue its refrigerative circulation in the evaporative portion 44 of the secondary refrigerant circuit 42. The pumping action continues until the level of the liquid refrigerant in the vessel 52 drops to a level which depends on the heat supplied to the tube portion 51. When this level is reached, no further liquid is pumped and the vapor generated by the portion 51 merely opposes the flow of refrigerant from the condensive portion 46 so that this flow is forced through the tube 64 and into the pipe 52. The evaporative portion 44 and the condensive portion 46 of the secondary circuit 42 are of ample capacity so that the temperature of the lower compartment 2!! depends only upon the quantity of refrigerant which is forced room, but little refrigeration is needed for the storage chamber l2. In such a cold room, the refrigeration mechanism 2| operates only for a small proportion of the total time and the portion 58 of the capillary tube is not very warm so that but little vapor is formed in the lower portion 51 of the tube 55 and but little pumping action takes place, Consequently, but little liquid is passed to the evaporative portion 44 and the liquid level in the trap will be near the upper end of the pipe 62.

When the room, in which the refrigerator I0 is located, warms up to a high temperaturefthe refrigeration mechanism 2| will operate for a greater portion of the time and the portion 58 of the capillary tube 32 will be warmer than in the cold room because of the more active operation of the refrigeration apparatus 2| and because. of the higher temperature of the air which cools the condenser 28. The higher temperature of the capillary tube portion 58, in turn, will cause a more active formation of vapor in the lower portion 51 of the vertical tube 55, and consequently; a more violent pumping action in the upper portion 56 of the'tube 55, so that more refrigerant liquid is passed into the open end of the pipe 62 and-more refrigerant liquid fiows to the evaporative portion 44 and cools the lower cbmpartment 20.

Under these conditions, the liquid level of the refrigerant in the trap will drop to a low level such as indicated by the line 98. Room temperatures intermediate the temperatures given in the aforementioned two examples will produce correspondingly intermediate refrigeration in the lower compartment 20 so that the temperature of this comthat one inch of capillary tube 32 tightly clamped 1 to the tube portion 5! produced an approximately constant temperature of F. in the lower compartment 20 for ambient temperatures of the refrigerator varying between 70 F. and 110 F. A greater length of capillary tube clamped to the tube portion 51 produced a drop in the lower compartment temperature when the ambient tem perature rose and a shorter length of the capillary tube allowed the lower compartment temperature to rise with the ambient temperature.

It will be observed that the cooling efiect produced by the vaporization of liquid refrigerant in the lower portion of the tube 51 is not lost but is transmitted to the refrigerant flowing in the capillary tube 32.

Modifications the evaporative portion 44 is, effected somewhat in the same manner as in the previously-described modification.

The action of the modification shown in Fig. 6 4

is similar to that shown in Figs. 1, 2, 3 and 4, and the apparatus is merely a simplification of that shown in these figures. Like parts have been designated by like reference numerals. In Fig. 6, the condensive portion 16 of the secondary volatile refrigerant circuit comprises a single tube of a diameter sufficient to pass refrigerant vapor and the refrigerant liquid in counterflow. The refrigerant vapor is introduced into the condensive portion 16 by direct connection with the exit end of the evaporative portion 44 and a raised portion 15 is provided so that the refrigerant liquid running downwardly from the condensive portion 16 cannot flow in a reverse directioninto the evaporative portion 44 but is forced to flow into the vertical tube 10.

The pipe 80, which corresponds in function to the pipe 62 of Figs. 1, 2, 3 and 4, is inclined towards an opening 82 in the tube 10 to receive the refrig- It will be readily apparent that varibe expelled through the opening 82 and which may be formed in the vessel 52, to the condensive portion 16.

' Another modification of this invention is shown in Fig. 7 and like parts have been provided with the same reference numerals used in Figs. 1, 2, 3 and 4. In this modification, a-portion 86 of the primary evaporator 22 is wound around in heat exchange relationship with the metal wall of the vessel 52, so that this vessel acts as a condenser for the refrigerant vapor of the secondary circuit as well asa. trap for the refrigerant liquid thereof. In this modification the exit end 88 of the vertical tube 90 is shown as bent towards the upper open end of the pipe 92. The tube 90 and the pipe 92 correspond in function 'to the tube 55 and the pipe 62 of the first-described modification. The exit end 94 is connected through a raised portion 96 with the pipe 92 and the lower portion of the pipe 92 is of sufficient size to pass the-refrigerant liquid and vapor therethrough in counterfiow.

The liquid level in the vessel 52, as shown in Fig.

for cooling said chamber, a volatile refrigerant in said circuit, and means for condensing the refrigerant vapor in said circuit to a liquid and for trapping said liquid, the combination with said refrigerator of a pump for transferring liquid refrigerant from said trapping means to said evaporator, said pump being actuated by the ambient temperature of said cabinet and adapted to pump a quantity of refrigerant which varies with said temperature, said variations in the quantity pumped being such that they substantially offset the variations of the heat leakage into said chamber caused by the variations in said ambient temperature.

3. In a refrigerator comprising a thermallyinsulated cabinet having a chamber; a mechanical refrigerating system including a primary evaporator; and a secondary volatile refrigerant circui't containing a volatile refrigerant and having an evaporative portion in heat-transferrelationship with said chamber, a condensive portion for condensing refrigerant vapor in said circuit to- I a liquid by heat transfer to said primary evaporapump for transferring the condensed liquid from 7, is low and is the level which the liquid would assume when the refrigerator is operating in a warm room. In this modification, the pump 90 pumps all'of the refrigerant liquid which fiows into the pipe 92 and a greater heat input into the lower portion 51 of the tube 90 is required than in the previously-described modifications. In each of the modifications shown in Figs. 6 and 7, the lower ends of the respective tubes 10 and 90 may be subjected to the ambient temperature of the refrigerator in the manner shown in Fig. 5.

It will be apparent from the above that this invention provides a simple means forvarying the refrigeration effect of a secondary volatile refrigerating system and that this means may be utilized to maintain two compartments in a refrigerator at desired temperatures in varying room temperatures and that only one primary refrigerant unit controlled by a single thermostat is needed for the source of refrigeration.

While I have shown my invention in several trapping said liquid, the combination with said" refrigerator of a pump for transferring refrigerant liquid from said trapping means to said evaporator, and an element which varies in temperature mainly with the ambient temperature of the cabinet, said pump being actuated by said element and adapted to pump a quantity of refrigerant which varies with the heat of said element, said variations in the quantity of refrigerant pumped being such that they tend to offset the variations of the heat leakage into said chamber caused by the variations in said ambient temperature.

2. In a "refrigerator comprising a thermallyinsulated cabinet having a chamber, a uniform pressure refrigerant circuit having an evaporator said trap to said evaporative portion, said trap and lift pump being adapted to contain all of the condensable liquid in said circuit and said pump being adapted to utilize some of said condensed liquid as the operating fiuidand being actuated by the heat of said element and in such a degree of heat transfer relation with said element that the quantity of refrigerant liquid pumped by said pump offsets the heat leakage from said ambient temperature into said cabinet.

4. In a refrigerator having a thermally-insulated chamber; a horizontal partition for dividing said chamber into two compartments; a cooling unit for the upper compartment; mechanical means including a thermostat for maintaining said cooling unit ata substantially constant refrigerating temperature; a secondary volatile refrigerant circuit having an evaporative portion for cooling the lower compartment, a condensive portion in heat-exchange relationship with said cooling unit, a volatile refrigerant in said circuit. and a trap for collecting the refrigerant liquid condensed in said condensive portion, the combination with said refrigerator cabinet of a vapor-actuated lift pump utilizing said refrigerant liquid as a working fluid for lifting refrigerant liquid from said trap; means for conducting refrigerant liquid lifted by said pump to said evaporative portion, the combined liquid refrigerant holding capacity of said trap and pump being substantially equal to the volume of the liquid refrigerant condensable from said secondary circuit by said cooling unit; and an element which varies in temperature at least partly with the ambient temperature of the thermallyinsulated chamber, said pump being actuated by the heat of said element and adapted to pump a quantity of refrigerant which varies with the heat of said element, said trap and pump being the sole refrigerant flow controlling devices in the secondary circuit.

5. In a refrigerator comprising a thermallyinsulated chamber; a mechanical refrigerating system including a compressor, a condenser, and a primary evaporator; a secondary volatile refrigerant circuit having an evaporative portion in heat-transfer relation with said chamber, a consaid primary evaporator for condensing refrig-.

erant vapor in said circuit to a liquid, and a trap for receiving said condensed liquid; the combination with said refrigerator ofa vapor-actuated lift'pump for transferring the condensed liquid from said trap to said evaporator, said pump being actuated by the ambient temperature of said insulated chamber and responsive in its erator cabinet, and a conduit connecting said condenser with said evaporator, means for controlling said refrigerant condensing apparatus to maintain the temperature of said evaporator substantially constant, a secondary volatile refrigerant circuit having an evaporative portion for. cooling the lower compartment, a condensive portion in heat-exchange relationship with said evaporator, and a volatile refrigerant liquid in said circuit, the combination with said refrigerator cabinet of a trap forcollecting the refrigerant liquid condensed in said condensive portion, a vapor-actuated lift pump utilizing said refrigerant liquid as a working fluid for lifting refrigerant liquid from said tram. said pump having constantly open entrance and discharge ports,

said compressor to maintain the temperature of said primary evaporator substantially constant; a secondary volatile refrigerant circuit having an evaporative portion in heat-transfer relation with said chamber; a condensive portion in heattransfer relation with saidprimary evaporator for condensing refrigerant vapor in said circuit to a liquid; and a trap for receiving said condensed liquid, said trap being at a, higher elevation than said evaporative portion; the combination with said refrigerator of a vapor-actuated lift pump for transferring the condensed liquid from said trap to said evaporative portion, said pump being adapted to utilize some of said condensed liquid as the operating fluid and being actuated by the heat of said conduit, said trap and lift pump being adapted to contain substantially all of the condensable liquid in said circuit, said-pump and conduit being so proportioned that the heat of the conduit controls the quantity of liquid refrigerant supplied to said evaporative portion.

'7. In a refrigerator comprising a thermallyinsulated cabinet having a chamber therein, a mechanical refrigerating system including a compressor, a condenser cooled by the ambient air of said cabinet, an evaporator, and a conduit for transferring liquefied refrigerant from the condenser to the evaporator, thermostatic means for controlling the operation of said compressor to maintain the temperature of said primary evaporator substantially constant, a secondary volatile refrigerant circuit having an evaporative portion in heat-transfer relation with said chamber and a vessel in heat transfer relationship with said primary evaporator for condensing the-refrigerant vapor said circuit to a liquid and for trapping substantially all of said liquid, said vessel being at a higher elevation than said evaporative portion, the combination with said refrigerator of a pump for transferring the liquid refrigerant from said vessel to said evaporative portion, said pump being actuated by, and its ing the upper compartment, refrigerant condensing apparatus including a compressor, a condenser cooled by the ambient air of the refrigand means for conducting the refrigerant liquid lifted by said pump to said evaporative portion, the combined liquid refrigerant holding capacity of said trap and pump being substantially equal to the volume of the liquid refrigerant condensable from said secondary circuit by said evaporator, said pump being actuated by the heat of said conduit and responsive to the degree of heat thereof, said condensing portion discharging condensed refrigerant into said pump adjacent the discharge port of said pump and in counterfiow to the flow of refrigerant through said pump.

9. In a refrigerator, the combination of a thermally-insulated chamber, a primary cooling unit, a secondary refrigerant circuit including an evaporative portion for cooling said chamber, a condensive portion in heat exchange relationship with said primary cooling unit,'a vapor-lift pump having an intake port and a discharge port, said pump being arranged to receive liquid refrigerant from said condensive portion adjacent its discharge port, and a trap for the refrigerant liquid received by said pump, said trap communicating with the intake port of said pump, said trap and pump being adapted to hold the entire quantity of refrigerant liquid condensable by said condensing portion, said pump being actuated by the ambient temperature of said thermally insulated chamber to lift refrigerant liquid from said trap and supply it to said evaporative portion, said pump also being arranged to exert a pressure of said liquid at said discharge port responsive to the degree of said temperature, whereby the discharge pressure exerted by said pump opposes the flow of refrigerant from said condensive portion to said trap and forces said refrigerant liquid to flow through the discharge port of said pump to said evaporative portion, the quantity of liquid refrigerant supplied to said evaporative portion being thereby made responsive to said ambient temperature.

l0. Ina refrigerator cabinet having a thermally insulated chamber, a partition for dividing said chamber into a first and a second compartment, said first and second compartments being adapted to be maintained at different temperatures from one another, an evaporator for cooling said first compartment, refrigerant condensing apparatus including a compressor, a condenser cooled by the ambient temperature of the refrigerator cabinet, and a conduit connecting said condenser with said evaporator, means for controlling said refrigerant condensing apparatus to maintain the temperature of said evaporator substantially constant, a secondary volatile refrigerant circuit having an evaporative portion for cooling said second compartment, a condensive portion in heat-transfer relationship with said evaporator, and a volatile refrigerant in said circuit, the combination with said refrigerator cabinet of a trap for collecting the refrigerant liquid condensed in said condensive portion, said trap being at a, higher elevation than said evaporative portion, a vapor actuated lift pump utilizing said refrigerant liquid as a working fluid for lifting refrigerant liquid from said trap, and means .for conducting the refrigera'nt liquid lifted by said pump to said evaporative portion, the combined liquid refrigerant holding capacity of said trap and pump being at least equal to the volume of liquid refrigerant condensible from said secondary circuit by said evaporator, said pump being in heat-transfer relationship with said conduit and actuated by the heat thereof, said refrigerant condensing apparatus, said heat transfer relation between the conduit and the pump, and the effectiveness of said pump being so inter-related that the refrigerating effect of the refrigerant liquid lifted by said pump substantially ofisets the variations of heat leakage into said second compartment causedby variations in the ambient temperature of the refrigerator cabinet.

11. In a refrigerator cabinet having a thermally insulated chamber, a partition for dividing said chamber into a first and second compartment, said first and second compartments being adapted to be maintained at different temperatures from one another, an evaporator for cooling said first compartment, refrigerant condensing apparatus including a compressor, a condenser cooled by the ambient temperatureof the refrigerator cabinet, and a conduit connecting said condenser with said evaporator, means for controlling said refrigerant condensing apparatus to maintain the temperature of said evaporatbr substantially constant, a secondary volatile refrigerant circuit having an evaporative portion for cooling said second compartment, a condensive portion in heat-transfer relationship with said evaporator, and a volatile refrigerant in said circuit, the combination with said refrigerator cabinet of a trap for collecting the refrigerant liquid condensed in said condensive portion, a vapor actuated lift pump utilizing said refrigerant liquid as a working fluid for'liftlng refrig said conduit and actuated by the heat thereof, said refrigerant condensing apparatus, said heat transfer relation between the conduit and the pump, and the effectiveness of said pump' being so-inter-related that the refrigerating effect of the refrigerant liquid lifted by said pump substantially offsets the variations of heat leakage into said second compartment caused by variationsin the ambient temperature of the refrigerant liquid from said trap, means for separatthe volume of liquid refrigerant condensible from 4 said secondary circuit by'said evaporator, said pump being in heat-transfer relationship with erator cabinet.

12. Refrigerating apparatus comprising a vessel, means for supplying refrigerant liquid to said vessel, a refrigerant evaporator at a lower elevation than said vessel, a downwardly extending pipe connected at its lower end with said evaporator and at its upper end with an upper portion of said vessel, and a vapor actuated lift pump adapted and arranged to transfer refrigerant liquid from the lower portion of said vessel into the upper end of said pipe. v

13. The refrigerating apparatus defined in claim 12 wherein the vapor actuated lift pump comprises a downwardly extending tube, the lower end of said tube being closed, the upper end of said tube being operatively connected with the upper end of said pipe, said tube having an opening communicating with the lower portion of said vessel, and means for heating the lowerend of said tube to vaporize refrigerant liquid therein.

14. The refrigerating apparatus defined in claim 13 wherein the means for supplying refrigerant liquid to said vessel includes a conduit adapted and arranged todischarge refrigerant liquid into the upper end of said tube.

15. The refrigerating apparatus defined in claim 13 wherein the upper end of said tube communicates directly with the upper portion of said CARL F. ALSING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 21,040 Gibson Apr. 4, 1939 1,642,015 Cramer Sept, 13, 1927 2,138,612 Philipp Nov. 29, 1938 2,157,012 4 Philipp May 2, 1939 2.293.522

Thomas Aug.18, 1942 

